As for Irma, she's enjoying every minute of this. Not only because it feels like a novelty to her (he's actually the first man to ever accompany her back home.), but because she quite actually likes the company of the charming Monsieur Grantaire, and she does know she will miss him (even if only a bit) when they finally part.
It does surprise her to find herself thinking that she doesn't want this to end.

"You don't seem an ogre to me, Monsieur." she finally confesses "Ogres don't have such a way with words, and such a charming appearance."